1. Field of the Invention
The present invention concerns a manipulator, in particular a small robot, of the type having at least two limbs movable against one another by motor, and an axle drive which is acting on one motion axis of both limbs and that has an external rotor motor, a position transmitter and a transmission.
2. Description of the Prior Art
Manipulators in general have several limbs that are mutually movable in pairs, and that are connected in joints with each other to form the motion axes of the manipulator. Thus a typical six-axle articulated robot has a base, a carousel pivotable on the base around a vertical axis of rotation, a lever movable on the carousel around a horizontal axis of rotation, and an arm-hand-unit pivotably connected to the lever with an axis of rotation parallel thereto, composed of three axes of rotation perpendicular in pairs.
For mutual movement of the single limbs relative to each other, axle drives act on the respective single motion axes. Each such drive generally includes an electric motor, a position transmitter for the regulation of the driving mechanism, and a transmission for reduction of the output speed of the electric motor to the speed of the motion axis.
From DE 100 30 129 A1 a lightweight robot is known with an external rotor motor, a Hall-sensor as a position transmitter and a harmonic-drive-gear with a wave-generator is connected with the rotor of the electric motor, to reduce weight and dimensions. The robot limbs are supported mutually independently of the axle drive in order to maintain the robot kinematics also with a dismantled axle drive.
Disadvantageously such harmonic-drive gears are technically complicated small batch items, therefore preventing their use in small, light and non-expensive manipulators, for example, for schools and universities, as does the separate mounting of the robot limbs mutually against each other and the overall size resulting therefrom which is common in today's robots.